Multi-stage process for preparing N-alkyl-3,4-dialkyl-2,6-dinitroanilines

Abstract

A multistage process of preparing N-alkyl-3,4-dialkyl-2,6-dinitroanilines starts from 3,4-dialkyl phenol and goes through the stages of 3,4-dialkyl-2,6-dinitrophenol and 3,4-dialkyl-2,6-ditro alkoxybenzene, wherein the latter are new compounds.

We claim: 
     
       1. A process for preparing N-alkyl-3,4-dialkyl-2,6-dinitroanilines of the formula ##STR5## wherein R 1  is hydrogen, C 1  to C 6  straight or branched chain alkyl group; and R 2 , R 3  and R 4  are independently C 1  to C 6  straight or branched chain alkyl group optionally substituted by one or more halogen groups, characterized in that a. a 3,4-dialkyl phenol of the formula ##STR6##  is selectively nitrated with nitric acid in stage I in a two phase system to form 3,4-dialkyl-2,6-dinitrophenol of the formula: ##STR7## b. the 3,4-dialkyl-2,6-dinitrophenol in stage II is alkylated with an alkylating agent in the presence of a base and a catalytic amount of a phase transfer catalyst selected from the group consisting of   (R').sub.4 Q.sup.+ X--     wherein       R' may be the same or different C 1  to C 16  straight or branched alkyl groups, benzyl, substituted benzyl;   Q is N or P; and   X is Cl, Br, I or HSO 4  ;   a macrocyclic ether and polyethylene glycols of formula   HO--(CH.sub.2 CH.sub.2 O--).sub.n --CH.sub.2 CH.sub.2 OH       where n is an integer from 10 to 50,   in an organic solvent to form 3,4-dialkyl-2,6-dinitro alkoxybenzene of the formula: ##STR8##  where R 5  is an alkyl group having 1 to 6 carbon atoms; c. the 3,4-dialkyl-2,6-dinitro alkoxybenze is reacted in stage III with an amine of the formula ##STR9##  where R 1  and R 2  are defined above, in the presence of a catalytic amount of base or halide to form N-alkyl-3,4-dialkyl-2,6-dinitroaniline; and   d. the N-alkyl-3,4-dialkyl-2,6-dinitroaniline is recovered.     
     
     
       2. A process in accordance with claim 1 wherein the mole ratio of phenol to nitric acid in Stage I is from 1:2 to 1:4. 
     
     
       3. A process in accordance with claim 1 wherein the mole ratio of phenol to nitric acid in Stage I is from 1:2 to 1:2.5. 
     
     
       4. A process in accordance with claim 1 wherein the solvent of Stage I is chosen from the group consisting of dichloromethane, 1,2-dichloroethane, 1,1,1-trichloroethane, carbon tetrachloride, chloroform, trichloroethylene, tetrachloroethylene, chlorobenzene, dichlorobenzene, benzene, dialkylether and mixtures of these. 
     
     
       5. A process in accordance with claim 4 wherein the solvent of Stage I is dichloromethane. 
     
     
       6. A process in accordance with claim 1 wherein the alkylating agent of Stage II is selected from the group consisting of alkyl sulfate, alkylarylsulfonate, or alkyl halides. 
     
     
       7. A process in accordance with claim 6 wherein the alkylating agent of Stage II is dimethylsulfate or diethylsulfate. 
     
     
       8. A process in accordance with claim 1 wherein the phase transfer catalyst of Stage II is an alkyl or aralkylammonium halide. 
     
     
       9. A process in accordance with claim 8 wherein the phase transfer catalyst of Stage II is didecyldimethylammonium chloride, tricaprylmethyl ammonium chloride, or triethylbenzyl ammonium chloride. 
     
     
       10. A process in accordance with claim 1 wherein the solvent of Stage II is selected from the group consisting of acetone, methylethyl ketone, methyisobutyl ketone, cyclohexanone, cyclopentanone, dichloromethane, 1,2-dichloroethane, methylchloroform, carbon tetrachloride, benzene, toluene, xylene, cyclohexane and mixtures of these. 
     
     
       11. A process in accordance with claim 10 wherein the solvent of Stage II is dichloroethane or acetone. 
     
     
       12. A process in accordance with claim 1 wherein the amine of Stage III is a monoalkylamine. 
     
     
       13. A process in accordance with claim 1 wherein the mole ratio of amine to alkoxybenzene derivative of Stage III is from 2:1 to 6:1. 
     
     
       14. A process in accordance with claim 1 wherein the mole ratio of amine to alkoxybenzene derivative of Stage III is from 3:1 to 5:1. 
     
     
       15. A process in accordance with any of claim 1 wherein the catalyst of Stage III is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium chloride, barium bromide and lithium chloride. 
     
     
       16. A process in accordance with any of claim 15 wherein the catalysts of Stage III is calcium chloride or lithium chloride. 
     
     
       17. A process for preparing N-alkyl-3,4-dialkyl-2,6-dinitroaniline of the formula ##STR10## wherein R 1  is hydrogen, C 1  to C 6  straight or branched chain alkyl group; and R 2 , R 3  and R 4  are independently C 1  to C 6  straight or branched chain alkyl group optionally substituted by one or more halogen groups, characterized in that a. a 3,4-dialkyl-2,6-dinitrophenol of the formula ##STR11##  is alkylated with an alkylating agent in stage I in the presence of a base and a catalytic amount of a phase transfer catalyst selected from the group consisting of   (R').sub.4 Q.sup.+ X--     wherein       R' may be the same or different C 1  to C 16  straight or branched alkyl groups, benzyl, substituted benzyl;   Q is N or P; and   X is Cl, Br, I or HSO 4  ;   a macrocyclic ether and polyethylene glycols of formula   HO--(CH.sub.2 CH.sub.2 O--).sub.n --CH.sub.2 CH.sub.2 OH     where     n is an integer from 10 to 50,   in an organic solvent to form 3,4-dialkyl-2,6-dinitro alkoxybenzene of the formula: ##STR12##  where R 5  is an alkyl group having 1 to 6 carbon atoms; b. the 3,4-dialkyl-2,6-dinitro alkoxybenze is reacted in stage II with an amine of the formula ##STR13##  where R 1  and R 2  are defined above, in the presence of catalytic amount of base to form N-alkyl-3,4-dialkyl-2,6-dinitroaniline; and   c. the N-alkyl-3,4-dialkyl-2,6-dinitroaniline is recovered.     
     
     
       18. A process in accordance with claim 17 wherein the alkylating agent of Stage II is selected from the group consisting of alkyl sulfate, alkylarylsulfonate, or alkyl halides. 
     
     
       19. A process in accordance with claim 18 wherein the alkylating agent of Stage II is dimethylsulfate or diethylsulfate. 
     
     
       20. A process in accordance with claim 17 wherein the phase transfer catalyst of Stage II is an alkyl or aralkylammonium halide. 
     
     
       21. A process in accordance with claim 20 wherein the phase transfer catalyst of Stage II is didecyldimethylammonium chloride tricapylmethyl ammonium chloride, or triethylbenzylammonium chloride. 
     
     
       22. A process in accordance with claim 17 wherein the solvent of Stage II is selected from the group consisting of acetone, methylethyl ketone, methyisobutyl ketone, cyclohexanone, cyclopentanone, dichloromethane, 1,2-dichloroethane, methylchloroform, carbon tetrachloride, benzene, toluene, xylene, cyclohexane and mixtures of these. 
     
     
       23. A process in accordance with claim 22 wherein the solvent of Stage II is dichloroethane or acetone. 
     
     
       24. A process in accordance with claim 23 wherein the amine of Stage III is a monoalkylamine. 
     
     
       25. A process in accordance with claim 17 wherein the mole ratio of amine to alkoxybenzene derivate of Stage III is from 2.1 to 6.1. 
     
     
       26. A process in accordance with claim 17 wherein the mole ratio of amine to alkoxybenzene derivative of Stage III is from 3.1 to 5.1. 
     
     
       27. A process in accordance with claim 17 wherein the catalyst of Stage III is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium chloride, barium bromide and lithium chloride. 
     
     
       28. A process in accordance with claim 27 wherein the catalyst of Stage III is calcium chloride or lithium chloride.